


Graveheart

by Sincognito



Category: Underfell - Fandom, Undertale (Video Game)
Genre: Amputation, Angst, Any nsfw content will be explicitly tagged in advance, Co-Written, Death, Depression, Edgepuff, Fluff, I mean this is Underfell people, Implied Death, M/M, Major Character Injury, Mental Instability, Multiverse Theory, Papyrusxedge, Resets, Slow Burn, Time Travel, possible future smut? :3, very much angst, what do ya'll expect
Language: English
Status: In-Progress
Published: 2017-12-18
Updated: 2018-05-01
Packaged: 2019-02-16 14:37:49
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 2
Words: 3,947
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13056009
Author URL: https://archiveofourown.org/users/Sincognito/pseuds/Sincognito
Summary: A small hiccup in space and time sends Boss through the multiverse and into Undertale. The world seems to be nothing short of sweet and rosy, but every rose has its thorns.**Co-written fic by Sincognito and Madmusemagister**





	1. Prologue

**Author's Note:**

> Please note that this fic is a co-written work and will have entries from both myself and from Madmusemagister. 
> 
> This current chapter was written by: Madmusemagister

Coming out of the forest, Boss immediately realizes something is strange. The snow is white and pristine other than footsteps, hardly a speck of dust among it. Everything feels too… cheery. He heads towards his house, but is shocked to find that someone has replaced his expert traps with puzzles! And not even well made ones! A literal child could solve these in minutes! In his disgust, he refuses to solve any of them, just jumping around them instead.

It isn’t until he sees some weird, grinning, soft imposter that it truly sinks in that something is very wrong here.

“Wowie! Yet another me! And this one is pointy! Hello pointy me! I like your boots!” the faker says.

What is he playing at? Is he trying to flatter me? Why? Boss huffs at the other, but sticks his chest out anyways. “Only the finest style for someone as great and terrible as I! What’s your business with me?”

His eyes scan over the other. Much like Boss, his spine is quite exposed from the front, but unlike Boss there’s nothing protecting the back of the spine either. Other him is also wearing a scarf, which Boss approves of if only for the sake of not being a hypocrite. However, beyond that the other’s clothes are absolutely ridiculous! That “armor” is flimsy at best and he doubts it’d offer any more protection than cardboard. And, well, the guy isn’t even wearing pants. Thankfully his weirdly round doppelganger has the decency to cover his pelvis with some kind of… bowl shaped thing, but beyond that he’s just wearing tights. Boss is pretty sure literal paper could cut those. Admittedly the other’s boots are probably a bit more functional for the slush and ice of Snowdin and the marshes of Waterfall, but they look silly!

Then Boss’s mind stalls as he processes something. “Wait, what do you mean ‘yet another me’?”

“Oh! Am I the first one you’ve met? Wowie! Welcome to Undertale! Nyeheheh!”

Boss narrows his eyes and prepares several sharpened bones for a ruthless attack! “Explain, now.”

The weird him grins, “Oh! Are we sparring? Great! You can go first!”

Boss’s jaw drops open in sheer incomprehension. He doesn’t understand this other monster, not in the least. Something’s wrong here. He doesn’t like it. His attack stalls.

“Hmm? Oh! Did you want me to take the first turn instead?”

“What are you going on about!” Boss snaps, stomping his boot in the snow.

“Sparring, I think? I’m guessing it works differently where you’re from?”

Boss’s temper snaps. “You will explain to me what is going on this instant or I will skewer you!” He doesn’t have time for this. He has to go patrol in his world and try to keep monsters from rendering themselves extinct before they can even get the last soul. The mutts that make up the rest of Snowdin’s guard sure aren’t going to do it! Plus, without him there, his 1 HP brother might as well go around naked with “free EXP” written on every bone in his body.

“Oh! Yes, I can do that! You see, one way or another this universe came to exist. Unfortunately, even someone as great as the Great Papyrus knows not how the universe came into existence. However, I know that from there, many offshoot timelines began to occur. Some are almost exactly the same as this world but with minor, largely inconsequential changes such as everyone having fabulous boots, and in others the similarities are purely superficial with the fundamental rules of the universe having been changed.”

Boss glares at his apparent counterpart, but the other doesn’t flinch at all from his wrathful gaze. Boss wants to say that means he’s telling the truth, but the utter lack of reaction disturbs him more than it should. He huffs and shifts his weight to one foot, hand on his hip.

“Alright, let’s say I believe you. What other versions of us do you know?” Maybe they’ll be more helpful than he is.

“Well there’s Stretch, Hickory – you kind of remind me of his brother actually, but much taller and more handsome – there’s this one universe with a giant mirror, one with a line on his face, the spikier counterpart of that one, and, wait…” the other regards him for a moment, then gasps, “Are you the spiky counterpart of me? Nyeheheheh! It’s so good to finally meet you!

“Oh, just a few ground rules, this universe is very not-murdery so please no killing! If a monster tries to fight you, make sure to wait your turn, and then spare them! Some are a bit moody, but usually they’ll get over it if you ACT a bit.

“In this world, it’s spare and be spared!”

Boss just stares. His mouth opens. His mouth closes. Nope, he’s done with this nonsense. Monsters who aren’t murdery? Does this squishy him even know what monsters are? They’re called monstrous for a reason! He refuses to believe that this world is really the sugar bowl this other him is making it out to be. Besides, what are all these monsters planning on doing when a human passes through? One sufficiently nasty human could clear out the Underground!

“Okay take me back home where things make sense now.”

“You’ll have to come with me to get Sans. The Great Papyrus is great at many things, but my brother is better at quantum physics.”

Boss grumbles, but acquiesces and follows the other. Letting an unfamiliar monster trail him like this, especially with his spine on display, not looking around, chattering about inane things like spaghetti and game night and candy, obviously this other him is a naïve idiot. He couldn’t even scare a Whimsun! Well, maybe he could spook this world’s version, but the ones from his world would probably just eat his fingers and run off.

With startling ease, they get to the other him’s house. It’s quite… festive. Seriously, who needs this many lights? His house is practically a beacon! Soft him fumbles through his inventory for some keys – at least they have that small precaution – and Boss glances over to the two mailboxes. One is seemingly empty, and the other is overflowing!

“Are you ever going to answer your damn mail?” Boss snips.

“Oh, that’s Sans’s, and I’m going to guess no.”

“What’s he got in there?”

“I don’t know! I’m not going to root through someone else’s mail like a savage!” Finally, Papyrus produces the key and sticks it in the lock.

Inside is, well, just as uncanny as outside. It fills Boss with an unpleasant feeling he can’t quite place. It looks like his house down to the rock on the table and the sock with the sticky notes, but it’s also not similar in the least. It’s too bright, the color scheme is wrong, the notes are more annoying than threatening, there’s not a single hole in the place, there’s no carefully constructed cage around the rock prisoner, and it’s just wrong.

The entire world seems to be some sanitized, sugar coated parody of his world, and he doesn’t trust it for a second. There’s no way it’s as sweet as it seems, no possible way! It must be like that spider bitch Muffet, sweet outside with a rotten core. He just has to find it, then everything will make sense again.

“Are you alright, pointy me?”

“I’m fine. Where the fuck is your bro?”

“Considering that I’m here, I’m guessing that he’ll pop into his room seemingly randomly in a few seconds. I just have to open the cabinet and he’ll play his, ugh, trombone.”

Boss doubts that’ll work, but weirdly round him does just that and on cue a weirdly round version of his brother plays a surprisingly intact trombone. Other him forgot to mention the dog though. There are now a few holes in their floor from his bone attacks.

Other Sans comes down, surprisingly unphased by Boss’s arrival. Boss snarls at him, but he just chuckles.

“Down Fido.”

“I AM NO ONE’S DOG!” Boss screeches, summoning dozens of bones pointed straight at the fake brother. He wouldn’t actually go through with it, it’s his brother, even if it isn’t, but wrong Sans probably doesn’t know that.

Then suddenly he’s wet. Other Papyrus has procured a spray bottle and is currently spraying him with water. “No! No attacking Sans! He only has one HP! Bad edgy me! Bad!”

The attack fizzles as Boss sputters indignantly. “I AM NOT A CAT EITHER! Even if cats are obviously superior!”

“I know, but it works with edgy Sans, so I thought it’d work with you too!”

Boss throws his hands in the air. “I’m done! I’m just done! Do whatever the fuck you do and get me back to my world already!” He plops down on the couch and crosses his arms.

“Language!” other Papyrus snaps.

“Eh, not really feeling like it,” soft Sans says. The little brat dares to sit on his legs. Big. Mistake. Edge hurls the skeleton across the room, but his impromptu flight is stopped short by his counterpart turning San’s soul blue. Other Sans lands on his feet, much to Boss’s annoyance.

Other him takes the worst Sans and they go do a thing, he doesn’t know nor care as long as it gets him home. Until then he… has nothing to do really, so he busies himself with cooking. They don’t have much variety, but they do have pasta ingredients, so he goes with that. He finishes up right as they walk in.

“Alright, think I found what world you’re from. It’s called Underfell by the way, apparently. Dunno how these names work, but they do. Just hop in the machine,” harmless Sans says.

“Finally!” Boss says. He stomps down and follows this weird joke that looks kind of like his brother. He’s a little surprised to see that other him isn’t here. He’s… disappointed? Tch, no, he doesn’t get disappointed. That other him is just an enigma is all. An enigma and a joke, a parody that while unnerving, also serves to be rather amusing and at least partly helpful. More than that though, he’s a puzzle. This whole world is, and while the way his world works necessitates traps, well…

He’s always loved puzzles.

Sans seems to read the questioning look on his face as he says, “Sent him to go get some spare parts. Didn’t want him following you back. Heh, you’re a bit rough around the edges, aren’t you?

“Here’s some advice.” The other Sans’s eyes go completely dark, grin seeming to widen to the point of being maniacal. “Go home, never come here again, and leave my brother alone. He doesn’t deserve to get caught up in all your Fell-verse murder bullshit.”

Boss scoffs, “I’ll do whatever the fuck I want, you little gremlin, and your brother is an adult, he can do whatever the fuck he wants. Now then, if you think I’m getting into some weird gadget, then you’re sorely mistaken.” He shoves the other in. “You first. How the fuck do you work this thing?”

“Like hell I’m going to-”

“Do it or I’ll dust you.”

The Sans pauses, then hisses out, “Red button. Always the red button.”

Boss nods and presses it. There’s a flash, and a distinct lack of dust, so he judges it, if nothing else, to be his best bet to get home. He finds himself in a room he only vaguely visits and sees the blue gremlin scrambling to put together their own version of the machine.

“Asshole,” dislikeable Sans huffs.

“Fix it well you hear me, or else you’re never getting home.”

If the multiverse is really a thing, then there’s no way in this long-forsaken world he’s going to stay ignorant of it. He’s the Great and Terrible Papyrus after all, and he’ll go wherever the fuck he damn well pleases!

But for now, he’d best inform Sans and the others that he’s back.


	2. Chapter 1

**Summary for the Chapter:**

> First official chapter of Graveheart. 
> 
> This chapter was again written by MadMuseMagister.

To his relief, the unexpected little excursion didn’t take too much time. There was yet another failed attempt at robbing a cinnabunny – by the same dolt who was so desperate for the taste of sugar coated rabbit that he tried that four hours ago – but Snowdin did not break out into full anarchy within the an hour or two he was gone, nor does it seem that anyone even noticed he left. He’s not sure whether that’s a good thing or not.

Boss stomps over to his favorite subordinate’s station and glares at the smaller skeleton.

“What the fuck are you doing?” he asks with an air of menace.

“Uh, I can explain?” says Sans, the proper, sharp toothed skeleton who has an actual sense of fashion.

He also has a strange love of mustard, which probably explains the numerous bottles scattered willy nilly around the station and creating a huge mess. Boss scrunches his nose at the mess and gives the other a death glare, resisting the urge to hug him in the sheer relief that the one HP skeleton is actually alive. He can’t afford to show affection, not in the open. If anyone assumes he’s going soft, then every monster and their dead ancestors will be tearing his ribs open in an attempt to eat his heartstrings. Instead, he grabs Sans by his collar, bringing him close enough to get an uncomfortably close view of his own sharp teeth. Sans shivers. Good. He shoves Sans back into his station and growls at him.

“I will return in ten minutes and if there is any inkling that this mess ever happened, then I’m assigning you to ‘stress relief’. For the mutts.”

Sans sputters, eyes wide and empty in horror. Boss turns around to attend to the rest of his duties, takes a few steps, and there’s the thump of Sans falling out of his seat in a panic to get the strewn about bottles cleaned and remove any stains.

Even Boss isn’t sure if he’d ever go through with the offer – he’s fairly certain the threat of his wrath would keep the dogs from doing anything too boneheaded – but as a one HP monster, Sans can’t really afford to take chances.

It’s almost too easy to slip back into the groove of things, as though no one actually noticed that he completely disappeared and left his duties unattended for hours. That’s a little too convenient, he doesn’t trust it. He should look around an-

“I will return in ten minutes and if there is any inkling that this mess ever happened, then I’m assigning you to ‘stress relief’. For the mutts.”

Sans sputters, eyes wide and empty in horror. Boss turns around to attend to the rest of his duties, takes a few steps, and there’s the thump of Sans falling out of his seat in a panic to get the strewn about bottles cleaned and remove any stains.

This is familiar, but he’s not completely sure why. It’s more than just “Sans is a slob who likes mustard too much” familiar, it’s “I’m pretty sure I recently lived this exact same thing” familiar. The same feeling of déjà vu has been far too prevalent recently, it’s starting to drive him insane.

It’s still better than that bizarre world though. He’s pretty sure he would’ve killed someone if he got one more creepy smile. Those monsters are too good at hiding their malice; everything looks clean and happy and sterilized. It reminds him of that mad scientist Alphys: all sweet and clean and harmless looking until you eventually find the melted together remains of missing monsters in the True Labs.

He tries to ignore the fact that this was approved by the crown, only halted because the resulting messes weren’t hostile enough to be of any real use unless hungry, at which point the nigh if not truly immortal beings swore loyalty to none.

The Guard Dogs have certainly been taking their jobs more seriously since hearing about their fate. Some had made some mention of killing the king, but as not a boss, but the Boss and Captain of the Snowdin Sect of the King’s Guard, he naturally struck them down and reminded them just how lucky they are to have someone as merciful as Asgore on the throne. After all, he could easily kill any random monster with hardly a thought, so they should be lucky he doesn’t come down and kill them himself.

Then behind closed doors, far away from spying eyes, he gave the brave, mourning dogs some bones and treats, reminding them that they are in fact very good dogs. Also, he reminded them that they would very quickly stop being a dog and start being dust if they mentioned a word of this. They took it well and nothing has been said.

He stops as he gets to one of his expertly laid traps, specifically a pit expertly crafted to skewer something roughly the same weight as a human, naturally calibrated as such to ensure the humans have minimal time to try to escape (and certainly not to try to spare lighter monsters who are just being stupid). It’s been tripped, leading to a gaping hole in the snow. Who dares step into the restricted area of the guard? He looks down with a look most menacing.

It’s Snowdrake. The idiot. He lets out a long suffering sigh and seriously contemplates just leaving the teen there, but no, he won’t. Snowdrake Senior took the news of what became of his wife quite… poorly. He shut everyone out to the point of violence until the inevitable happened. Snowdrake and Chilldrake were left without any parents and fled to the woods where at least the guards may have a chance of saving the teens – too old to be considered children – from any EXP hunters. Unfortunately, after realizing they had survived that time, several other teens also fled for the forests, so now the area is filled with oversized children who seem to think that this is going to work forever. (Secretly Boss hopes they’re right).

“How did you-? No, you know what, just stand still and I’ll lift you out. Be glad you birds or whatever you are are light, and I’m not fixing any injuries you sustained. You can beg your brother for that,” Boss scoffs. He turns the monster’s soul blue, changing gravity first to up, and then to his right and sending the teen directly into a tree. As soon as the whelp recovers from his daze, he stutters out a quiet thank you and runs off.

Now he has to cover this trap up again. No one is going to willingly jump into a pit of spikes after all. How annoying. After that he has to –

~~~~~

“I will return in ten minutes and if there is any inkling that this mess ever happened, then I’m assigning you to ‘stress relief’. For the mutts.”

Sans sputters, eyes wide and empty in horror. Boss turns around to attend to the rest of his duties, takes a few steps, and there’s the thump of Sans falling out of his seat in a panic to get the strewn about bottles cleaned and remove any stains.

This is familiar, but he’s not completely sure why. It’s more than just “Sans is a slob who likes mustard too much” familiar, it’s “I’m pretty sure I recently lived this exact same thing” familiar. The same feeling of déjà vu has been far too prevalent recently, it’s starting to drive him insane.

He doesn’t have time for this. He has to go check to make sure none of the idiot teenagers who decided the restricted area was the best place to live fell into any of his traps. He’d rather not have to clean dust out of all the parts.

There’s a Snowdrake in the spike trap, Jerry got caught by a rope (Boss left him), and his deadly bridge trap has a fresh layer of dust on it, too big to be any teenager. It smells like burnt dog hair. He leaves it.

He gets home and-

~~~~~~

“I will return in ten minutes and if there is any inkling that this mess ever happened, then I’m assigning you to ‘stress relief’. For the mutts.”

Sans sputters, eyes wide and empty in horror. Boss turns around to attend to the rest of his duties, takes a few steps, and there’s the thump of Sans falling out of his seat in a panic to get the strewn about bottles cleaned and remove any stains.

He knows he’s done this before, but he spares no time to contemplate this before breaking into a sprint towards the bridge. Had he checked that yesterday? No, he had to attend to a fight in the town and it was left forgotten.

He gets to the bridge and begins inspecting the various traps for any possible fault. This is the only one that is supposed to be activated, a bottleneck acting as a last defense should a human try to cross into Snowdin. Then he notices it, the flamethrower is acting up. For one of his weight, it’ll do nothing, but it would fry a heavier monster alive if they stepped too close and set it off. He immediately gets to work on fixing it.

Partway through Doggo shows up, and Papyrus waves him away until he’s confident the flamethrower won’t turn him into one of Sans’s infernal Hot Dogs a la dust. Once it’s done, he turns around. He’s not sure why, but he’s pretty sure there’s something in the spike pit.

After freeing Snowdrake, he goes home to make sure the Not-Sans is actually doing its job. He jabs his key into the basement and-

~~~~~

After freeing Snowdrake, he goes to make sure the Not-Sans…

Shit, again? He doesn’t feel any urgent needs so it’s probably nothing major, but he should still check. He jabs his key into the basement and sees the Not-Sans with the squishy him? No, not squishy him, but similar. This one holds himself too differently, not to mention the change in attire. This imposter’s is even worse, wearing track pants and an orange hoodie. Not even a proper coat, a hoodie!

“Heh, take a picture, it might last more than a few seconds.”

Boss opens his mouth to ask and-

~~~~~~

He goes to make sure the Not-Sans and… not-him? Why does he assume a not-him will be there?

Ugh, he was right, and this skeleton is quite tacky. They’re working together on the machine, but very not-him gives him a smile that doesn’t sit right.

Make sure Not-Sans and not-him…

~~~~~~

Make sure Not-Sans and not-him…

~~~~~~

Make sure Not-Sans and not-him…

~~~~~~ 

Make sure Not-Sans and not-him…

~~~~~~

Make sure Not-Sans and not-him…

~~~~~~

“Okay that’s enough of this. I don’t care if it isn’t calibrated properly, let’s go my edgy dude,” very not him says. Very not-him pings his soul blue, throws him into the machine and hops in after him.

Boss immediately prepares to skewer not-him when they tumble back out again, but the asshole disappears. He thought only Sans could do that!

With a huff, Boss stomps out, but pauses at the door. He peeks out and- 

Oh, he’s back in the sugar bowl… probably. Stepping out, it’s like someone took the world and just flipped the directions. The forest is to the east instead of the west like it’s supposed to be. That’s going to get disorienting fast.

“Heh, good to be home. Welcome to Underswap you fucking edgelord,” says the orange hoodie wearing parody of himself. 

Boss screeches.


End file.
